Glucose levels in the blood rise after a meal. This increase stimulates the β-cells in the islets of Langerhans to secrete insulin. Insulin has effects on several tissues: liver, adipose tissue, muscle tissue and other body cells. In general insulin stimulates glucose uptake. In the liver and in muscle tissue insulin also induces glycogen synthesis. These events result in a decrease of the blood glucose levels to normal values. In adipose tissue the synthesis of triglyceride is stimulated.
The physiological regulation of glucose uptake is depicted below. After
I. Insulin has a plasma half-life of 10-20 minutes. II. Fasting induces secretion of insulin.
Extra info: Insulin has a short half-life of 10-20 minutes. Fasting inhibits the secretion of insulin, because plasma glucose levels decrease.